In air conditioner technology it is desirable to run the air conditioner unit as efficiently as possible both to save on energy and to save wear and tear on the air conditioner. One way to improve efficiency is to spray a fine mist of water on the evaporative condenser. The condenser of the air conditioner is often located outside of the building or space being conditioned. The idea is to improve heat transfer from the condenser by wetting the surface of the metal pipes and fins that make up the condenser""s heat transfer system.
A number of attempts have been made to perfect this type of wetting system. U.S. Pat. No. 4,685,308 to Welker et al discloses one such system. Water for the misters is usually supplied from a tap. Typically something then trips a valve to activate the mist when the A/C unit is running. In the case of Welker the system detects a high temperature to initiate mist flow. The idea is to supply water in the form of mist only when it is needed and to avoid excessive flow when not needed. Misting the condenser when it is not running hot can result in the condenser freezing up, which reduces efficiency to near zero and can ruin the unit. Excess water also results in waste and undesirable amounts of water on the ground around the unit.
Prior art devices have attempted to measure some indicator that the condenser is running such as vibration, heat or airflow to indicate a need for mist. The problem is that these are not true measures of the need for mist. The true measure of the need for mist cooling is the head pressure of the refrigerant leaving the condenser to return to the evaporator. This head pressure is a true indicator of the need for mist. As the head pressure increases past a designed pressure the unit will lose efficiency. Misting the condenser will reduce the head pressure. Another problem with prior art units is that they introduce a device with components that the air conditioner service technician is not familiar with.
The present invention solves the limitations of the prior art devices. The current invention provides an air conditioner condenser mist device activated only as the head pressure in the coolant leaving the condenser exceeds a certain preset level. The current device provides a mister that uses valves and systems with which most air conditioner service people are already familiar. The current invention provides a reliable system with a minimum of moving parts.